Arresting the rate of land clearing: Change in woody native vegetation cover in a changing agricultural landscape

Understanding the magnitude and drivers of background vegetation change at the landscape scale is an important step towards improving management strategies and policy. This study examined historical (1946–2008) and contemporary (2004–2008) change in extent of native trees in three case study areas in central Victoria, Australia using aerial photographs. To investigate the drivers and impacts of the documented change we used aerial photograph interpretation and workshops with landholders and natural resource management agency staff.By 1946 much of the clearing in each case study had already occurred leaving native tree cover at 5–38% across the three regions. From 1946 to 2008 there was a slight net decrease in tree cover in all three case study areas. Spontaneous regeneration and revegetation, mapped using 2004–2008 aerial photographs, accounted for 1.9 and 1.0% gain of the case study areas respectively. In each region the gain in extent of immature trees was greater than the net loss of mature trees, excluding remnant paddock trees. Across all case study areas socio-economic factors, including commodity prices, government legislation and natural resource management incentives were the predominant and persistent determinants of vegetation change.Attempts to increase the extent and quality of native vegetation in the landscape needs to consider: the impact of large-scale drivers of vegetation change; the biodiversity value of the regenerating vegetation compared to existing remnants and active revegetation.

► Examined the magnitude and drivers of change in the extent of native trees.
► A majority of clearance occurred prior to 1946.
► Net loss in continuous canopy of native trees in two of the three case study areas.
► Socio-economic drivers were the predominant determinants of vegetation change.
► Bio-physical drivers were important but exhibited more spatial variability.